In manufacturing electronic devices, various processes are performed on a workpiece, e.g., a wafer. As for the processes performed on the workpiece, film formation is known. A film forming system is used for film formation. The film forming system generally includes a film forming apparatus and a transfer module. The film forming apparatus is, e.g., a sputtering apparatus. The transfer module is configured to transfer a workpiece to the film forming apparatus.
The transfer module of the film forming system needs to transfer the workpiece such that a central position of the workpiece coincides with a predetermined position in the film forming apparatus. Therefore, the film forming system further includes a sensor such as a camera. A deviation from the central position of the workpiece detected by the sensor is obtained and a workpiece transfer position of the transfer module is corrected based on the positional deviation. A technique for correcting the workpiece transfer position is disclosed in Japanese Patent Application Publication No. 2008-306162.
The film forming apparatus may need to form a film only on a circular region inward of the circular edge of the workpiece among the entire surface of the workpiece. Therefore, the film forming apparatus is configured to arrange a mask with a circular opening corresponding to the circular region inward of the circular edge of the workpiece during the film formation on the workpiece.
However, if a central position of the workpiece is deviated from a central position of the opening of the mask, a central position of the film is deviated from the central position of the workpiece. Accordingly, a material forming the film may be attached to, e.g., a backside of the workpiece. In addition, when a multilayer film is formed on the workpiece by forming a film on the workpiece in each of a plurality of film forming apparatuses, individual films of the multilayer film may have different central positions.
Therefore, the difference between the central position of the film formed on the workpiece and the central position of the workpiece needs to be reduced or removed.